Shark skin microbial communities

Sampling the microbes from the skin surface of a juvenile whale sharks in La Paz, Mexico

SEM image of the skin surface of a Leopard shark (Triakis semifasciata). The individual scales are called dermal denticles, which are a teeth like structures that cover the skin of the shark.Juvenile Whale shark swimming in La Paz Bay in Baja Sur, MexicoMichael Doane (left) and Dovi Kacev (right) aboard the Outerbanks participating in the annual common thresher shark survey of the California Bight that NOAA Southwest Fisheries Division supports.

Sharks are an important group of marine top predators, influencing trophic cascades through predation (1) and behavioral modification (2). Sharks are also evolutionarily unique from bony fishes, diverging from > 400 million years ago (3), with contemporary species emerging approximately 190 million years ago (4). In the past century, sharks have experienced drastic population declines due to over fishing activities. Another less studied, yet equally great concern is how habit decline may alter shark health. The marine environment is being altered by anthropogenic factors, and this is associated with increased disease prevalence among marine organisms (5, 6). As many diseases are the result of microbial activity gone awry (7), this drives necessity for understanding microbial dynamics. Taken for granted, however is that all organisms host a collection of microbial organisms termed the microbiome and provide mutual and beneficial services to the host’s everyday functioning (8, 9). In order to understand how microbes influence the health of host organisms, we first must understand patters for microbial association with their host organisms and additionally factors that instigate fluctuation in microbial community dynamics of the microbiome (10). My dissertation research aims to bring attention to the microbiome at the skin interface of sharks. My questions focus on developing ecological underpinning of the shark skin microbiome dynamics. In the Dinsdale lab, we are using next-generation sequencing to compare snap-shots of the microbial communities on the skin and from the surrounding water column. Some shark species I have worked with include common thresher shark (Alopias vulpinus), whale shark (Rhincodon typus), and leopard sharks (Triakis semifasciata).